SEARCH · PubMed Health

Results for “Preterm”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,153 records · Page 64Linked to original sources

PubMed2000

The prevalence of thromboembolic events among women with extended bed rest prescribed as part of the treatment for premature labor or preterm premature rupture of membranes.

OBJECTIVE: This study was undertaken to determine the prevalence of thromboembolic events among women with extended bed rest prescribed as part of the treatment of premature labor or preterm premature rupture of membranes. STUDY DESIGN: A retrospective chart review was undertaken of all women who had bed rest of >/=3 days' duration prescribed as part of the treatment of premature labor or preterm premature rupture of membranes in the Akron General Medical Center Perinatal Unit during the period January 1, 1997-December 31, 1998. The prevalence of thromboembolic events in this population was determined. The charts of all additional gravid women with antepartum or postpartum deep vein thrombosis or pulmonary embolism diagnosed during the study period were also reviewed. The prevalence of these disorders among the pregnant population for whom extended bed rest was not prescribed as part of the treatment of premature labor or preterm premature rupture of membranes was also calculated. Statistical comparison of the prevalences in the 2 populations was undertaken by means of the chi(2) analysis with the Fisher exact test. RESULTS: There were 192 patients admitted during the study period who had extended bed rest prescribed as part of the treatment of premature labor or preterm premature rupture of membranes. Three of these women had thromboembolic events, for a prevalence of 15.6 cases per 1000 women. Five additional gravid women were admitted for the treatment of deep vein thrombosis or pulmonary embolism. There were 6164 deliveries among women not treated with extended bed rest for premature labor or preterm premature rupture of membranes during this period. Thus the prevalence of these phenomena among the remaining pregnant women was 0.8 cases per 1000 women. The prevalences of these disorders in the 2 populations were highly significantly different. CONCLUSION: The prevalence of thromboembolic events among women for whom extended bed rest is prescribed as part of the treatment of premature labor or preterm premature rupture of membranes is significantly increased with respect to that among gravid women who do not receive this therapy and is substantially higher than previously reported. If this finding is confirmed in other populations, it may be prudent to undertake further studies to determine whether this prevalence can be reduced.

Bed Rest↗

PubMed2001

Association between colonization with group B streptococci during pregnancy and preterm delivery among Danish women.

OBJECTIVE: We studied the relationship between group B streptococcal colonization and preterm delivery. STUDY DESIGN: In this prospective study at a single hospital in Odense, Denmark, cervicovaginal cultures were obtained at < or = 24 weeks' gestation from all the women, at delivery from women with preterm deliveries, and from a random sample of women delivering at term. RESULTS: In 2846 singleton births, there was no significant association between group B streptococcal colonization at <or = 24 weeks' gestation and preterm birth. After adjustment for the risk factors for preterm delivery, more women with preterm delivery (12/84, 14%) were colonized at delivery with group B streptococci than women with term deliveries (22/300, 7%; adjusted odds ratio, 3.0; 95% confidence interval, 1.4-6.8). Group B streptococcal colonization at < or = 24 weeks' gestation and at delivery was significantly less likely to occur in the presence of normal vaginal flora. CONCLUSION: Group B streptococcal colonization at delivery, but not at < or = 24 weeks' gestation, was associated with preterm delivery.

Adult↗

PubMed2001

Pregnancy outcome in women with preterm labor symptoms without cervical change.

OBJECTIVE: This study was undertaken to determine pregnancy outcome in women who have preterm labor symptoms without cervical change according to fetal fibronectin status. STUDY DESIGN: Patients who were examined at the obstetric emergency department with symptoms of preterm labor but without cervical change underwent fetal fibronectin collection. Pregnancy outcome and fetal fibronectin results were analyzed after delivery. RESULTS: Of the 235 patients sampled, 20% (n = 48) had positive fetal fibronectin results. The mean +/- SD gestational age at delivery was lower in women with positive fetal fibronectin results (34.2 +/- 4.1 vs 37.7 +/- 2.3 weeks; P <.001); these women were more likely to deliver preterm as a result of preterm labor than women with other obstetric indications (46% vs 19%; P <.001). Infants born to these women demonstrated lower birth weight (2317 +/- 895 g vs 2877 +/- 557 g; P =.003), were more likely to be admitted to the neonatal intensive care unit (42% vs 14%; P <.001), and were more likely to die in the neonatal period (11% vs 0%; P <.001). CONCLUSION: Patients with symptoms of preterm labor but without cervical change who have negative fetal fibronectin results are less likely to deliver preterm. Therefore in women with symptoms but without cervical change fetal fibronectin should be considered for risk assessment.

Adult↗

PubMed2001

Clinical significance of intra-amniotic inflammation in patients with preterm labor and intact membranes.

OBJECTIVE: The purpose of this study was to determine the frequency and clinical significance of intraamniotic inflammation in patients with preterm labor and intact membranes. STUDY DESIGN: Amniocentesis was performed in 206 patients with preterm labor and intact membranes. Amniotic fluid was cultured for aerobic and anaerobic bacteria and mycoplasmas. The diagnosis of intraamniotic inflammation was made in patients with a negative amniotic fluid culture on the basis of amniotic fluid concentrations of interleukin-6 (>2.6 ng/mL, derived from receiver operating characteristic curve analysis). Statistical analysis was conducted with contingency tables and survival techniques. RESULTS: Intra-amniotic inflammation (negative amniotic fluid culture but elevated amniotic fluid interleukin-6) was more common than intra-amniotic infection (positive amniotic fluid culture regardless of amniotic fluid interleukin-6 concentration; 21% [44/206 women] vs 10% [21/206 women]; P <.001). The amniocentesisto-delivery interval was significantly shorter in patients with intra-amniotic inflammation than in patients with a negative culture and without an inflammation (median, 20 hours [range, 0.1-2328 hours] vs median, 701 hours [range, 0.1-3252 hours], respectively; P <.0001). Spontaneous preterm delivery of <37 weeks was more frequent in patients with intra-amniotic inflammation than in those with a negative culture and without inflammation (98% vs 35%; P <.001). Patients with intra-amniotic inflammation had a significantly higher rate of adverse outcome than patients with a negative culture and without intra-amniotic inflammation. Adverse outcomes included clinical and histologic chorioamnionitis, funisitis, early preterm birth, and significant neonatal morbidity. There were no significant differences in the rate of adverse outcomes between patients with a negative culture but with intra-amniotic inflammation and patients with intra-amniotic infection (positive culture regardless of amniotic fluid interleukin-6 concentration). CONCLUSION: Intra-amniotic inflammation/infection complicates one third of the patients with preterm labor (32%; 65/206 women), and its presence is a risk factor for adverse outcome. The outcome of patients with microbiologically proven intra-amniotic infection is similar to that of patients with intra-amniotic inflammation and a negative amniotic fluid culture. We propose that the treatment of patients in preterm labor be based on the operational diagnosis of intra-amniotic inflammation rather than the diagnosis of intra-amniotic infection because the latter diagnosis cannot be undertaken rapidly.

Amniocentesis↗

PubMed2001

Phenotypic and metabolic characteristics of maternal monocytes and granulocytes in preterm labor with intact membranes.

OBJECTIVE: Experimental and clinical studies support a role for the fetus in the control of the onset of labor. Fetal systemic inflammation, but not a maternal inflammatory response, has been linked to the onset of preterm labor and delivery on the basis of the determination of inflammatory cytokines in fetal and maternal blood. We propose that parturition requires fetomaternal cooperation and that inflammation is an integral part of the parturitional process. This study used flow cytometry, a sensitive technique for the detection of intravascular inflammation, to assess whether maternal inflammation is present in preterm labor. STUDY DESIGN: A prospective cross-sectional study was performed including patients with preterm labor (n = 55) and women with normal pregnancy (n = 50). Intravascular inflammation was studied by using flow cytometry. Maternal blood was assayed to determine granulocyte and monocyte phenotype by using monoclonal antibodies, which included the following cluster of differentiation (CD) markers: CD11b, CD14, CD15, CD16, CD18, CD49d, CD62L, CD64, CD66b, and HLA-DR. Oxidative burst and generation of basal intracellular oxygen radical species were assessed. Statistical analysis was conducted with the use of nonparametric methods. A P value of <.01 was considered statistically significant. RESULTS: Preterm labor was associated with a significant increase in the median mean channel brightness of CD11b, CD15, and CD66b on granulocytes and median mean channel brightness of CD11b and CD15 on monocytes. The ratio of oxidative burst over basal intracellular oxygen radical species in both granulocytes and monocytes was increased in preterm labor (P <. 01). CONCLUSION: Preterm labor with intact membranes is associated with phenotypic and metabolic changes of maternal granulocytes and monocytes.

Adult↗

PubMed2002

Risk of preterm birth that is associated with vaginal douching.

OBJECTIVE: The purpose of this study was to examine the association between vaginal douching and preterm birth. STUDY DESIGN: We enrolled hospitalized women after delivery in a case-control study. Women who were delivered of a live preterm singleton infant were assigned as cases. Women who were delivered at term were randomly selected as control subjects. We surveyed women about their douching habits and risk factors for preterm birth and abstracted data from the records. RESULTS: After adjustment, vaginal douching within 6 months of pregnancy was not significantly associated with preterm birth (odds ratio, 1.1; 95% CI, 0.8-1.6). However, in secondary analyses, douching more than once per week (odds ratio, 4.0; 95% CI, 1.0-15.5) or longer than 10 years (odds ratio, 1.9; 95% CI, 1.1-3.2) was associated with preterm birth. CONCLUSION: Vaginal douching does not appear to be a strong risk factor for preterm birth. Further study is needed to confirm the risk that is associated with frequent or long-term douching.

Adult↗

PubMed2002

Polymorphism in the interleukin-1 gene complex and spontaneous preterm delivery.

OBJECTIVE: We examined the association between preterm delivery and polymorphisms at position +3953 of the interleukin-1 beta gene (IL1B+3953) and in intron 2 of the interleukin-1 receptor antagonist gene (IL1RN). STUDY DESIGN: This was a case-control study that involved 52 pregnancies that resulted in spontaneous preterm delivery before 34 weeks of gestation and 197 pregnancies that resulted in birth at term. Polymorphisms were determined by polymerase chain reaction and restriction fragment length polymorphism analysis. RESULTS: Homozygous carriage of IL1B+3953 allele 1 by fetuses of African descent was associated with a risk of preterm delivery (P =.033). Fetuses of Hispanic descent that carried IL1RN allele 2 were found to be at an increased risk for preterm premature rupture of membranes and subsequent preterm delivery(P =.021; odds ratio, 6.5; 95% CI, 1.25-37.7). CONCLUSION: There are associations of spontaneous preterm delivery with the fetal carriage of IL1B+3953*1 and IL1RN*2 alleles in African and Hispanic populations, respectively.

Adult↗

PubMed2002

Preterm premature rupture of the membranes is associated with a reduction in neonatal respiratory distress syndrome.

OBJECTIVE: The purpose of this study was to evaluate the effect of preterm premature rupture of the membranes on the frequency of respiratory distress syndrome among singleton pregnancies that are complicated with preterm delivery. STUDY DESIGN: We performed a retrospective analysis of singleton pregnancies that were delivered between 24 and 34 weeks of gestation. Patients were categorized on the basis of membrane integrity into two groups: ruptured versus intact. All patients received prophylactic antibiotics and a single course of antenatal betamethasone. Data were analyzed with the Student t test, the chi(2) test, and the Fisher exact test. Multiple logistic regression analysis was performed to examine the effect of possible confounding variables that were considered risk factors for respiratory distress syndrome. Probability values of <.05 for all two-tailed tests were considered significant. RESULTS: A total of 366 patients were included (99 patients in the preterm premature rupture of the membranes group and 267 patients in the intact membranes group). Patients were delivered at 30.7 +/- 2.9 and 30.1 +/- 2.7 (mean +/- SD) weeks of gestation, with birth weights of 1620 +/- 594 and 1417 +/- 501 g, respectively. The frequency of respiratory distress syndrome in the neonate was significantly lower in the preterm premature rupture of the membranes group than in their intact counterparts (17% vs 39%, P <.001). Multiple logistic regression analysis confirmed that preterm premature rupture of the membranes (odds ratio, 0.16; 95% CI, 0.08-0.34) was independently associated with a reduction in the frequency of respiratory distress syndrome. CONCLUSION: In the clinical setting of delivery before 34 weeks of gestation, preterm premature rupture of the membranes is associated with a significant decrease in the frequency of neonatal respiratory distress syndrome.

Adult↗

PubMed2003

Antepartum fetal asphyxia in the preterm pregnancy.

OBJECTIVE: The objective of this report was to provide insight into the frequency and characteristics of antepartum fetal asphyxia in pregnancies that are delivered preterm. STUDY DESIGN: The characteristics of 30 pregnancies that were delivered preterm with biochemically confirmed antepartum fetal asphyxia (umbilical artery base deficit of >12 mmol/L) that were derived from >1 decade of experience in a single tertiary care obstetric unit were examined. Antepartum clinical characteristics, fetal assessment tests, and neonatal complications were documented. Fetal asphyxia was classified as mild, moderate, or severe on the basis of an umbilical artery base deficit (>12 mmol/L) and newborn encephalopathy and other organ system complications. RESULTS: Antepartum fetal asphyxia accounted for at least 34% of the fetal asphyxia in the pregnancies that were delivered preterm. Predictive criteria that led to intervention and diagnosis included clinical risk factors and, particularly, abnormal fetal assessment tests. The 50% incidence of moderate or severe asphyxia in the antepartum preterm pregnancies compares with 15% in term pregnancies. Moderate or severe asphyxia occurred with equal frequency with early and delayed intervention. CONCLUSION: Fetal asphyxia in pregnancies that were delivered preterm is present frequently before the onset of labor. Abnormal fetal assessment tests are valuable predictors of antepartum fetal asphyxia. The increased frequency of moderate and severe fetal asphyxia in the pregnancy that is delivered preterm implies a greater likelihood of long-term morbidity or death.

Asphyxia↗

PubMed2003

Therapeutic effect of cyclo-oxygenase inhibitors with different isoform selectivity in lipopolysaccharide-induced preterm birth in mice.

OBJECTIVE: Cyclo-oxygenase inhibitors have different selectivity for inhibitory action on the isoforms of the enzyme. Our purpose was to compare the tocolytic and maternal toxic effects of various cyclo-oxygenase inhibitors in the lipopolysaccharide-induced preterm birth in pregnant mice. STUDY DESIGN: We randomly assigned 50 ICR pregnant mice into five groups of 10 mice each and treated them intraperitoneally with either phosphate-buffered saline solution or lipopolysaccharide (50 microg) on day 15 of pregnancy. Of the four groups that received lipopolysaccharide, three groups also were treated either with nonselective cyclo-oxygenase inhibitors (indomethacin [1 mg/kg/d] or diclofenac [2 mg/kg/d]) or with the cyclo-oxygenase-2 preferential inhibitor, meloxicam (2 mg/kg/d), with a gavage tube on days 15 through 18 of pregnancy or until maternal death. The mice were killed immediately after preterm birth or on day 21 of pregnancy. Preterm birth rates and maternal side effect profiles were evaluated. RESULTS: Preterm birth occurred in 90% of mice after intraperitoneal lipopolysaccharide injection and in 20% of mice after phosphate-buffered saline solution injection. Indomethacin and meloxicam, but not diclofenac, significantly decreased the incidence of preterm birth that was induced by lipopolysaccharide (33.3% and 33.3%, respectively; P =.028). Although the overall incidence of maternal gastric and/or renal toxicities was not significantly increased in the indomethacin or meloxicam groups, a significant increase was noticed in the diclofenac group compared with the lipopolysaccharide-treated control group (P =.006). CONCLUSION: Indomethacin and meloxicam, but not diclofenac, inhibit the lipopolysaccharide-induced preterm birth in an animal model. Meloxicam appears to have no advantage over indomethacin with regard to tocolysis and maternal side effects.

Animals↗

PubMed2000

The role of swallowing during active sleep in the clearance of reflux in term and preterm infants.

OBJECTIVES: To investigate swallowing and peristalsis in sleep and during gastroesophageal reflux (GER) in both healthy term and preterm infants at term equivalent age. STUDY DESIGN: Multichannel recordings were made in 12 healthy term and 11 preterm infants, under the same conditions, after feeding. Sleep state, cardiorespiratory variables, esophageal pH, and pharyngeal swallowing and peristalsis were measured. GER was defined as pH <4 for > or = 15 seconds, and swallows were classified as pharyngeal only, primary peristalsis (propagated, dropped, interrupted), or secondary peristalsis. RESULTS: Spontaneous swallowing rate was not significantly different between term and preterm infants and was sleep state-related, occurring in active sleep but rarely in quiet sleep. In response to acid GER, term infants significantly increased pharyngeal swallowing from a median of 0.7 (25th-75th interquartile range, 0.5-0.9) to 1.7 (1.0-3.0) swallows/min and secondary peristalsis from a median of 0.5 (25th-75th interquartile range, 0.3-0.8) to 1.1 (0.8-2.0) waves/min (P <.05). In contrast, the preterm infants demonstrated a significantly higher proportion of fully propagated peristaltic swallows compared with the term infants (53% and 27%, respectively) (P <.05). CONCLUSION: The occurrence of swallowing is sleep state-related. In active sleep, term infants clear GER by increasing swallowing and secondary peristalsis, whereas preterm infants at term equivalent age clear GER by increasing propagated peristalsis. This method of clearance would explain the mechanism by which preterm infants have significantly shorter episodes of reflux than term infants.

Deglutition↗

PubMed2003

Catch-up growth of head circumference of very low birth weight, small for gestational age preterm infants and mental development to adulthood.

OBJECTIVE: To examine the influence of postnatal energy quotient (EQ, energy intake/kg body weight per day) on head circumference (HC) growth and mental development of very low birth weight (VLBW), small for gestational age (SGA, <10th percentile) preterm infants. STUDY DESIGN: SGA VLBW preterm infants (n = 46) with primarily symmetric intrauterine growth restriction were compared with 62 appropriate for gestational age (AGA) VLBW preterm infants and 73 term infants from the Bonn Longitudinal study. RESULTS: Twenty-seven of 46 (59%) of the SGA preterm infants showed complete HC catch-up growth by the age of 12 months, but mostly before 6 months after term (HC catch-up group). These infants had significantly higher mean EQs from day 2 to 10 than the group of 19 infants without HC catch-up (EQ, 95 vs 78). Mean EQs correlated significantly with developmental and intelligence quotients (DQ/IQ) from 18 months to 6 years. As adults, the HC of the HC catch-up group was not significantly different from that of the AGA preterm infants, the term infants, and their parents. The group without HC catch-up had smaller HC as adults. CONCLUSIONS: Our data suggest that early postnatal high-energy nutrient intake for SGA preterm infants is needed to promote HC catch-up growth and to prevent negative consequences of undernutrition.

Adolescent↗

PubMed2003

Neurologic examination of preterm infants at term age: comparison with term infants.

OBJECTIVES: The aim was to establish the range of neurologic findings in preterm infants reaching term age, their relation to gestational age at birth, and the possible differences with healthy term newborns tested during the first days of life. STUDY DESIGN: The Dubowitz neonatal neurologic examination was performed at term age in 157 low-risk preterm infants born between 25 and 34 weeks' gestation who had cranial ultrasonograms that were normal or showed minor abnormalities. Infants were subdivided in 3 groups according to their gestational age at birth. RESULTS: Within the preterm cohort, the range of scores for the 3 gestational age subgroups was different from each other for 21 of the 34 items, although the median scores were different only in 10 of the 34 items. The range of scores and their median in preterm infants however was wider than that found in term infants. Preterm infants examined at term were also more hyperexcitable and tended to have less flexor tone in the limbs and less extensor tone in the neck in the sitting posture. CONCLUSIONS: The distribution of scores provides useful guidelines when a preterm infant is examined at term.

Female↗

PubMed2003

Failure of physiologic transformation of the spiral arteries in patients with preterm labor and intact membranes.

OBJECTIVE: The purpose of this study was to determine whether abnormal placentation (defined as the failure of physiologic transformation of spiral arteries) is present in patients with preterm labor and intact membranes who delivered a preterm neonate. STUDY DESIGN: A cross-sectional study was conducted to examine the histopathologic findings in the placental bed and placenta of patients with preterm labor and intact membranes (n=27), preeclampsia (n=43), and healthy pregnant women at term (n=103). Immunohistochemistry studies with cytokeratin 7 and periodic acid-Schiff were used to detect trophoblast and fibrinoid, respectively, and diagnose the failure of physiologic transformation of the spiral arteries. RESULTS: The mean percentage of spiral arteries with failure of physiologic transformation in the myometrium was significantly higher in patients with preterm labor and preeclampsia than in normal pregnant women at term (P=.0004 and P<.0001, respectively). Similar findings were observed in the decidual segment of spiral arteries within the placental bed (P=.001 and P<.0001). In contrast, the mean percentage of the spiral arteries with failure of physiologic transformation in the decidua of the basal plate was not significantly different between patients with preterm labor and normal pregnant women (P=.17). CONCLUSION: Failure of physiologic transformation of the spiral arteries in the myometrial and decidual segments of the placental bed is frequent in patients with preterm labor and intact membranes.

Adult↗

PubMed2002

Executive functions in preschool children born preterm: application of cognitive neuroscience paradigms.

Although children born preterm are at risk for neuropsychological impairments at school age and adolescence, including difficulties with visual motor integration, spatial/constructional skills, attention, arithmetic, and nonverbal executive functions, specific neuropsychological outcome has not been investigated adequately in preschoolers. Application of cognitive neuroscience tasks offers the opportunity to characterize early executive functions in young children born preterm. In a preliminary sample of 29 preschool children born preterm (M birth gestational age = 32.4 weeks), executive function outcome was compared to that of fullterm controls by contrasting performance on two prototypic delayed-response-type paradigms, Delayed Alternation and Spatial Reversal. Preschoolers born preterm correctly retrieved the reward on fewer trials on Delayed Alternation than did matched controls. Furthermore, preschool children born preterm used problem-solving strategies that included more perseverative errors than controls. These preliminary findings highlight the utility of cognitive neuroscience paradigms to understand neuropsychological outcome in preschool children born preterm and suggest areas of developmental vulnerability that may include dorsolateral prefrontal circuits.

Child, Preschool↗

PubMed2006

Is sonographic assessment of cervical length better than digital examination in screening for preterm delivery in a low-risk population?

BACKGROUND: This randomized controlled trial compared the diagnostic accuracy of the sonographic assessment of cervical length and clinical digital examination of the cervix in the second trimester regarding the prediction of preterm delivery in a low-risk population. METHODS: In total, 282 unselected, asymptomatic women with singleton pregnancy randomly underwent sonographic cervical length measurement (study group, n=138) or clinical digital examination (control group, n=144) in the second trimester. In the study group cervical length or=95th percentile (>or=4) for our population was defined as high. The primary outcome measure was the diagnostic accuracy of both tests regarding the prediction of preterm delivery (<37 weeks). RESULTS: Shortened cervical length was found in 6/138 (4.3%) women whereas the high Bishop score was found in 17/144 (11.8%) (p=0.038, Fisher's exact test). The incidence of preterm delivery was 5.7% (16/282). Regarding the prediction of preterm delivery, shortened cervical length and high Bishop score had sensitivity 57.1% versus 33.3% and positive predictive value 66.7% versus 17.6%. Shortened cervical length in comparison with high Bishop score had 12-fold higher positive likelihood ratio for preterm delivery in a low-risk population (37.4; 95%CI [8.2-170.7] versus 3.2; 95%CI [1.1-9.2]). CONCLUSION: Sonographic assessment of cervical length has better diagnostic accuracy in the prediction of preterm delivery compared to digital examination in a low-risk population.

Adult↗

PubMed2006

Does peripheral auditory threshold correlate with brainstem auditory function at term in preterm infants?

CONCLUSION: Peripheral auditory threshold does not correlate with brainstem auditory function in preterm infants. Infants with peripheral auditory abnormality seem not to be necessarily more prone to brainstem auditory abnormality than those without the elevation, although further studies are needed in a larger number of subjects. OBJECTIVE: To investigate whether peripheral auditory threshold correlates with brainstem auditory function in preterm infants and shed light on whether preterm infants with threshold elevation are prone to central auditory abnormality. PATIENTS AND METHODS: Brainstem auditory evoked response (BAER) was recorded with clicks at term in preterm infants (gestation 28-36 weeks). Analysis of correlation was made between BAER threshold and various BAER components. BAER data were compared between preterm infants with thresholds < or = 20 dB nHL (n = 113) and those > 20 dB (n = 32). RESULTS: Although BAER threshold correlated significantly with BAER wave latencies and amplitudes, the threshold did not correlate significantly with I-V, I-III and III-V intervals. No significant differences were found between preterm infants with BAER thresholds < or = 20 dB and those > 20 dB in I-V, I-III intervals, although III-V was longer in the infants with thresholds > 20 dB nHL (p < 0.05).

Audiometry, Evoked Response↗

PubMedDate not supplied

Acute effects of total suspended particles and sulfur dioxides on preterm delivery: a community-based cohort study.

The acute effects of air pollution on preterm delivery were examined in a prospective cohort in Beijing, China. From early pregnancy until delivery in 1988, we followed all registered pregnant women who lived in four residential areas of Beijing. Information for both mothers and infants was collected. Daily air pollution and meteorological data were obtained independently. The sample for analysis included 25,370 resident women who gave first live births in 1988. Multiple linear regression and logistic regression were used to estimate the effects of air pollution on gestational age and preterm delivery (i.e., < 37 wk), with adjustment for outdoor temperature and humidity, day of the week, season, maternal age, gender of child, and residential area. Very high concentrations of ambient sulfur dioxide (mean = 102 micrograms/m3, maximum = 630 micrograms/m3) and total suspended particulates (mean = 375 micrograms/m3, maximum = 1 0003 micrograms/m3) were observed in these areas. There was a significant dose-dependent association between gestational age and sulfur dioxide and total suspended particulate concentrations. The estimated reduced duration of gestation was .075 wk (12.6h) and .042 wk (7.1 h) for each 100-micrograms/m3 increase in sulfur dioxide and total suspended particulates 7-d lagged moving average, respectively. The adjusted odds ratio for preterm delivery was 1.21 (95% CI = 1.01-1.46) for each in micrograms/m3 increase in sulfur dioxide, and was 1.10 (95% CI = 1.01-1.20) for each 100-micrograms/m3 increase in total suspended particulates. In addition, the gestational age distribution of high-pollution days was more skewed toward the left tail (i.e., very preterm and preterm), compared with low-pollution days. We concluded that high levels of total suspended particulates and sulfur dioxide, or of a more complex pollution mixture associated with these pollutants, appear to contribute to excess risk of preterm delivery in this population. Further work need to be carried out, with more detailed information on personal exposure and effect modifiers.

Adult↗